Often, signal processing circuits include an amplifier, such as a programmable gain amplifier (PGA). Such signal processing circuits may be configured to perform audio signal processing, video signal processing, image processing, and control operations (such as motor control operations), to name a few of many possible applications. Sometimes, a relatively low-power circuit, such as micro-control unit (MCU) or a sensor, may be coupled to a relatively high-power circuit, such as a motor control inverter, a switched mode power supply, or a direct current (DC) to alternating current (AC) inverter for solar conversion. In such cases, a high impedance interface may be used to connect the circuits, allowing for implementation of passive filters, such as protection resistors, breakdown diodes, and the like.